(1) Field of the Invention
This invention relates to a high contact density electrical connector which is not of the conventional pin-and-socket configuration.
(2) Description of the Prior Art
Tapered fasteners are frequently used in the fabrication of aircraft wing and body structures. Their effectiveness in forming a quality joint is often critically dependent on the size, shape, and finish of the hole into which they are inserted. Accurate inspection of such tapered holes, usually numbering in the thousands for a single aircraft, has led to the development of a computer aided analysis technique, in the form of a capacitance sensing probe which is inserted into the structural holes. This inspection technique is considered to be a significant improvement, in terms of manhours expended and measurement reliability, over more conventional means of nondestructive inspection such as boroscope or visual comparison, and use of a profilometer, dye check, protrusion check or air gage.
The inspection method developed uses a segmented capacitance type probe tip formed by having a pattern of conductive paths on the outer surface of the probe tip coated with a high dielectric insulator. When the probe tip is inserted into the hole to be in spected, multiple capacitors are formed between the conductive segments on the probe tip and the metallic walls of the hole. The actual capacitance of each segment is electronically measured and computer analyzed to ascertain the critical parameters associated with that hole.
A variety of fabrication and operational constrains qualify the design of the probe tip. For example, the probe tip must be suitable for use in a production environment; it must be capable of evaluating holes of diameters no more than 0.48 cm; it requires about ten individual conductive segments; and it must be mounted in a connector which maintains accurate and repeatable dimensional tolerances, thereby mitigating the deleterious effects of stray capacitance. Furthermore, with an application entailing repeated insertion of the probe tips into holes in comparatively hard metals such as titanium, and the potential need for changing tip sizes to inspect holes of other dimensions, the capability to replace the probe tips easily, at the point of inspection, is of distinct advantage. Because of this replaceability requirement, the probe tip dimensions, the large number of electrical contacts, and foremost, the critical effects of stray capacitance, the use of conventional connector, such as a pin and socket type, or such variations thereof as shown in U.S. Pat. No. 4,054,346 is not feasible.